Window-covering term

Blackout

A light-control configuration designed to minimize incoming light using opaque material and attention to edge coverage.

Why it matters

Material, installation gaps, and the window itself affect the outcome.

Last reviewed: 2026-08-06 · Editorial basis and linked source records.

A configuration intended to reduce incoming light substantially without necessarily eliminating edge gaps.

A treatment installed within the window opening.

A treatment installed on wall or trim outside the window opening.